Matthew 12:34-35
You brood of vipers, how can you speak good when you are evil? For the mouth utters what the heart is full of.
Luke 6:45
The good man produces good from the good stored in his heart, and the evil man evil from his evil: for a man's mouth utters what his heart is full of.
Matthew 15:19
For out of the heart come evil designs, murder, adultery, sexual vice, stealing, false witness, and slander.
Mark 7:21-23
From within, from the heart of man, the designs of evil come: sexual vice, stealing, murder,
Mark 14:38
Watch and pray, all of you, so that you may not slip into temptation. The spirit is eager but the flesh is weak."
Hebrews 12:15
see to it that no one misses the grace of God, that no root of bitterness grows up to be a trouble by contaminating all the rest of you;
James 1:14-15
Everyone is tempted as he is beguiled and allured by his own desire;